How Well do Probability Experts Assess Probabilities?
Technical rept. Jan-Aug 80,
DECISION RESEARCH EUGENE OR
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Past research on peoples ability to assess probabilities has shown two common errors, overconfidence in ones knowledge and insensitivity to task difficulty. This research has created a new class of experts those who have studied probability assessors and who are aware of the common errors. The performance of eight such experts is here compared to the performance of twelve untrained subjects and fifteen who had previously received training in probability assessment. All subjects responded to 500 general-knowledge items whose difficulty could be measured a priori from the item context. The experts appeared to have overcorrected for the overconfidence error they were notably underconfident, whereas the untrained subjects were overconfident and the trained subjects were mixed. The experts were more sensitive than the other two groups to variations in item difficulty. However, even they showed a substantial insensitivity to difficulty, relative to ideal performance. Introspection suggests that this second error would be hard to overcome. Author
- Statistics and Probability